#include <iostream>
#include <iomanip>
using namespace std;
template <typename T1, typename T2>
T1 demo21(T2 a)
{
    return a;
}
template <typename T>
class demo2
{
public:
    typedef T value_type;
    value_type A;
};
int main(int argc, const char **argv)
{
    cout << setprecision(20);
    cout << demo21<double>(1.21 / 3.12) << endl;
    return 0;
}